// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/version.h"

#include <stddef.h>

#include <algorithm>

#include "base/logging.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_split.h"
#include "base/strings/string_util.h"

#if defined(WIN32)
#undef max
#undef min
#endif

namespace base {

namespace {

    // Parses the |numbers| vector representing the different numbers
    // inside the version string and constructs a vector of valid integers. It stops
    // when it reaches an invalid item (including the wildcard character). |parsed|
    // is the resulting integer vector. Function returns true if all numbers were
    // parsed successfully, false otherwise.
    bool ParseVersionNumbers(const std::string& version_str,
        std::vector<uint32_t>* parsed)
    {
        std::vector<StringPiece> numbers = SplitStringPiece(version_str, ".", KEEP_WHITESPACE, SPLIT_WANT_ALL);
        if (numbers.empty())
            return false;

        for (auto it = numbers.begin(); it != numbers.end(); ++it) {
            if (StartsWith(*it, "+", CompareCase::SENSITIVE))
                return false;

            unsigned int num;
            if (!StringToUint(*it, &num))
                return false;

            // This throws out leading zeros for the first item only.
            if (it == numbers.begin() && UintToString(num) != *it)
                return false;

            // StringToUint returns unsigned int but Version fields are uint32_t.
            static_assert(sizeof(uint32_t) == sizeof(unsigned int),
                "uint32_t must be same as unsigned int");
            parsed->push_back(num);
        }
        return true;
    }

    // Compares version components in |components1| with components in
    // |components2|. Returns -1, 0 or 1 if |components1| is less than, equal to,
    // or greater than |components2|, respectively.
    int CompareVersionComponents(const std::vector<uint32_t>& components1,
        const std::vector<uint32_t>& components2)
    {
        const size_t count = std::min(components1.size(), components2.size());
        for (size_t i = 0; i < count; ++i) {
            if (components1[i] > components2[i])
                return 1;
            if (components1[i] < components2[i])
                return -1;
        }
        if (components1.size() > components2.size()) {
            for (size_t i = count; i < components1.size(); ++i) {
                if (components1[i] > 0)
                    return 1;
            }
        } else if (components1.size() < components2.size()) {
            for (size_t i = count; i < components2.size(); ++i) {
                if (components2[i] > 0)
                    return -1;
            }
        }
        return 0;
    }

} // namespace

Version::Version()
{
}

Version::Version(const Version& other) = default;

Version::~Version()
{
}

Version::Version(const std::string& version_str)
{
    std::vector<uint32_t> parsed;
    if (!ParseVersionNumbers(version_str, &parsed))
        return;

    components_.swap(parsed);
}

Version::Version(std::vector<uint32_t> components)
    : components_(components)
{
}

bool Version::IsValid() const
{
    return (!components_.empty());
}

// static
bool Version::IsValidWildcardString(const std::string& wildcard_string)
{
    std::string version_string = wildcard_string;
    if (EndsWith(version_string, ".*", CompareCase::SENSITIVE))
        version_string.resize(version_string.size() - 2);

    Version version(version_string);
    return version.IsValid();
}

int Version::CompareToWildcardString(const std::string& wildcard_string) const
{
    DCHECK(IsValid());
    DCHECK(Version::IsValidWildcardString(wildcard_string));

    // Default behavior if the string doesn't end with a wildcard.
    if (!EndsWith(wildcard_string, ".*", CompareCase::SENSITIVE)) {
        Version version(wildcard_string);
        DCHECK(version.IsValid());
        return CompareTo(version);
    }

    std::vector<uint32_t> parsed;
    const bool success = ParseVersionNumbers(
        wildcard_string.substr(0, wildcard_string.length() - 2), &parsed);
    DCHECK(success);
    const int comparison = CompareVersionComponents(components_, parsed);
    // If the version is smaller than the wildcard version's |parsed| vector,
    // then the wildcard has no effect (e.g. comparing 1.2.3 and 1.3.*) and the
    // version is still smaller. Same logic for equality (e.g. comparing 1.2.2 to
    // 1.2.2.* is 0 regardless of the wildcard). Under this logic,
    // 1.2.0.0.0.0 compared to 1.2.* is 0.
    if (comparison == -1 || comparison == 0)
        return comparison;

    // Catch the case where the digits of |parsed| are found in |components_|,
    // which means that the two are equal since |parsed| has a trailing "*".
    // (e.g. 1.2.3 vs. 1.2.* will return 0). All other cases return 1 since
    // components is greater (e.g. 3.2.3 vs 1.*).
    DCHECK_GT(parsed.size(), 0UL);
    const size_t min_num_comp = std::min(components_.size(), parsed.size());
    for (size_t i = 0; i < min_num_comp; ++i) {
        if (components_[i] != parsed[i])
            return 1;
    }
    return 0;
}

int Version::CompareTo(const Version& other) const
{
    DCHECK(IsValid());
    DCHECK(other.IsValid());
    return CompareVersionComponents(components_, other.components_);
}

const std::string Version::GetString() const
{
    DCHECK(IsValid());
    std::string version_str;
    size_t count = components_.size();
    for (size_t i = 0; i < count - 1; ++i) {
        version_str.append(UintToString(components_[i]));
        version_str.append(".");
    }
    version_str.append(UintToString(components_[count - 1]));
    return version_str;
}

bool operator==(const Version& v1, const Version& v2)
{
    return v1.CompareTo(v2) == 0;
}

bool operator!=(const Version& v1, const Version& v2)
{
    return !(v1 == v2);
}

bool operator<(const Version& v1, const Version& v2)
{
    return v1.CompareTo(v2) < 0;
}

bool operator<=(const Version& v1, const Version& v2)
{
    return v1.CompareTo(v2) <= 0;
}

bool operator>(const Version& v1, const Version& v2)
{
    return v1.CompareTo(v2) > 0;
}

bool operator>=(const Version& v1, const Version& v2)
{
    return v1.CompareTo(v2) >= 0;
}

std::ostream& operator<<(std::ostream& stream, const Version& v)
{
    return stream << v.GetString();
}

} // namespace base
